Run results for: querySelectorAll: id vs tag vs class

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser: Chrome 87

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
find by id	161264.2 Ops/sec
find by class	182518.4 Ops/sec
find by tag	192241.4 Ops/sec

HTML Preparation code:

<div>
  <a id="tr_1" class="c-1">
    <span id="tr_2" class="c-2"></span>
  </a>
  <div id="tr_3" class="c-3"></div>
 </div>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.js'></script>

Tests:

find by id
document.querySelectorAll("#tr_1"); document.querySelectorAll("#tr_2"); document.querySelectorAll("#tr_3");
find by class
document.querySelectorAll(".c-1"); document.querySelectorAll(".c-2"); document.querySelectorAll(".c-3");
find by tag
document.querySelectorAll("a"); document.querySelectorAll("span"); document.querySelectorAll("div");

Run results for: querySelectorAll: id vs tag vs class

test which selector is better for find element

find by id

find by class

find by tag